ABSTRACT:
A number
of diverse kinds of magnetic experiments are shown to lead to the observation
of a Bose-Einstein condensation of magnons in some nanostructures, especially
in Fe and in Co/Pt. The experiments include 1) the measurement of magnetic
aftereffect, 2) measurements of Néel’s fluctuation field, including an estimate
of activation volume, 3) the measurement of the energy gap which provides a
lower limit on the BEC temperature, 4) using Lagrange multipliers in the quantum
thermodynamics of magnons, and 5) the observation of a visible anomaly in the
Bloch T3/2 law for the temperature dependence of magnetization of nanostructured
ferromagnets.